I think Jo has more to offer than we could see. Someone commented that Jo was boring bla bla and TJ was more exciting but I have different opinions. Jo is more stable and dependable which is what Ian needs. But yes you're right- Jo will have to toughen up (if he's not already- he just seems like a really cool and calm). I just don't see the fighter in him yet but that can change as he finds out how dangerous being by Ian's side becomes.
Now TJ- after what he did to Ian I have lost respect for him. Now Ian went to Jail for them so Jason's (dying in ICU) is leaving a great deal of money or something for Ian after his death. Ian does not want it but Jason is giving it anyways.
I always though TJ was the 2ML but now he's almost becoming the villain instead which is a shame, maybe he will have an arc towards the end. No idea what's going to happen but this story is interesting!!!